SCC is the second most common type of skin cancer. SCCs often look like scaly red patches, open sores, warts or elevated growths with a central depression. They may crust, bleed or become painful. Cumulative, long-term exposure to ultraviolet (UV) radiation from the sun, as well as indoor tanning, cause most SCCs. SCC can become disfiguring and sometimes metastasize if allowed to grow. These cancers can spread to the lymph nodes or other organs in some instances. Spread is more likely in patients that are immunosuppressed and/or if tumors have high-risk features. High-risk features for SCC include large size (diameter > 2cm), deeper depth of invasion into the skin, location on the ear or lip, and two other criteria best diagnosed under the microscope.

Melanoma (MM) is considered one of the most dangerous types of skin cancers. These tumors originate in the pigment-producing melanocytes in the basal layer of the epidermis. MM are thought to develop from moles but may also develop de novo. The majority of melanomas are black or brown, but some can also be skin-colored, pink, red, purple, blue or white. In general, MM may present as a mole that is asymmetric, has irregular borders or multiple colors, and is larger than a pencil tip eraser. MM is caused mainly by intense, occasional UV exposure (frequently leading to sunburns), especially in those who are genetically predisposed to the disease. The majority of MM diagnosed annually are in situ (non-invasive). This means they are confined to the epidermis (the top layer of skin). MM in situ (MIS) has a very high cure rate. Since the epidermis has no blood vessels or lymphatic channels, MIS theoretically cannot spread to the lymph nodes or other organs. That said, if these initially shallow tumors are left untreated and allowed to grow, they may expand and send roots into the deeper layers of the skin, resulting in possible metastasis and lower cure rates. The cure rates for invasive MM are mainly predicated on the depth of invasion, which can be measured when the lesion is biopsied. When detected early, MM is often treated and curable through local surgery. However, if the tumor has grown more deeply into the skin, surgical resection may be combined with examination of the lymph nodes, as well as other treatment options.

There are many additional rare forms of skin cancer, such as Merkel cell carcinoma, sebaceous carcinoma, adnexal carcinoma, dermatofibrosarcoma protuberans (DFSP), undifferentiated pleomorphic sarcoma, leiomyosarcoma, cutaneous T-cell or B-cell lymphomas, and others. Treatment will vary depending on the exact cancer type, its location on the body, and its clinical behavior and/or risk.

Actinic keratoses (AKs), also known as a solar keratoses, are crusty, scaly, rough red spots caused by damage from exposure to ultraviolet (UV) radiation. AKs are considered pre-skin cancers, because if left alone, they could theoretically develop into skin cancer, most often squamous cell carcinoma (SCC). Longstanding sun exposure is the biggest risk factor for the development of pre-skin cancers lesions. AKs typically appear on sun-exposed areas such as the face, scalp, ears, shoulders, neck and the back of the hands and forearms. They can also appear on other areas that exposed to the sun, such as the shins and other parts of the legs. On the lower extremities, these lesions are often elevated, rough in texture and resemble warts. The majority of AKs are asymptomatic but occasionally some can itch, burn or sting. Given their potential for turning into skin cancer, AKs should be treated. Several modalities can be used to effectively treat AKs, including liquid nitrogen, topical medications, such as Efudex (5-fluorouracil), Aldara (imiquimod), or in office treatments such as, chemical peels, photodynamic therapy (PDT) or lasers/light sources.